Scrollable result sets

JDBC provides two types of result sets that allow
you to scroll in either direction or to move the cursor to a
particular row. Derby supports one of
these types: scrollable insensitive result sets
(ResultSet.TYPE_SCROLL_INSENSITIVE).

When you use a result set of type of type
ResultSet.TYPE_SCROLL_INSENSITIVE, Derby materializes rows
from the first one in the result set up to the one with the biggest
row number as the rows are requested. The materialized rows will be
backed to disk if necessary, to avoid excessive memory usage.

Insensitive result sets, in contrast to sensitive result sets,
cannot see changes made by others on the rows which have been
materialized. Derby
allows updates of scrollable insensitive result sets; see Visibility of changes,
which also explains visibility of own changes.

Note: Derby does not
support result sets of type ResultSet.TYPE_SCROLL_SENSITIVE.

//autocommit does not have to be off because even if
//we accidentally scroll past the last row, the implicit commit
//on the the statement will not close the result set because result sets
//are held over commit by default
conn.setAutoCommit(false);
Statement s4 = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
s4.execute("set schema 'SAMP'");
ResultSet scroller=s4.executeQuery(
"SELECT sales_person, region, sales FROM sales " +
"WHERE sales > 8 ORDER BY sales DESC");
if (scroller.first()) { // One row is now materialized
System.out.println("The sales rep who sold the highest number" +
" of sales is " +
scroller.getString("SALES_PERSON"));
} else {
System.out.println("There are no rows.");
}
scroller.beforeFirst();
scroller.afterLast(); // By calling afterlast(), all rows will be materialized
scroller.absolute(3);
if (!scroller.isAfterLast()) {
System.out.println("The employee with the third highest number " +
"of sales is " +
scroller.getString("SALES_PERSON") + ", with " +
scroller.getInt("SALES") + " sales");
}
if (scroller.isLast()) {
System.out.println("There are only three rows.");
}
if (scroller.last()) {
System.out.println("The least highest number " +
"of sales of the top three sales is: " +
scroller.getInt("SALES"));
}
scroller.close();
s4.close();
conn.commit()
conn.close();
System.out.println("Closed connection");